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Crew members gather up the Red Bull Stratos balloon after Felix Baumgartner's second test flight in July. The balloon that carried him aloft in July was just one-quarter the size of the 55-story behemoth that will carry him to 120,000 feet on Monday. Photo: Red Bull Content Pool

The World’s Wildest Skydive Requires the World’s Biggest Balloon

This balloon, which carried Felix Baumgartner to an altitude of 13 miles in March, is 128 feet tall. Big, yes, but nothing compared to the 334-foot-tall monster that will carry him to the edge of the stratosphere on Monday. Photo: Jörg Mitter/Red Bull Content Pool

Late Sunday night, 15 men will clear every last stick and stone from a runway in the New Mexico desert as 10 more men wearing cotton gloves and protective suits unfurl and inflate the world’s largest helium balloon.

The job will take about eight hours, which seems like a long time until you realize the balloon weighs almost two tons and is taller than the Statue of Liberty. Simply filling it will take 45 minutes to an hour, which doesn’t seem long at all when you realize the balloon has a volume of 180,000 cubic feet.

This is no ordinary balloon. But then, this is no ordinary mission.

Crew members gather up the Red Bull Stratos balloon after Felix Baumgartner’s second test flight in July. The balloon that carried him to 97,145 feet in July was just one-quarter the size of the 55-story behemoth that will carry him to 120,000 feet on Monday. Photo: Red Bull Content Pool

The balloon will carry “Fearless Felix” Baumgartner to the edge of the stratosphere for his record-setting skydive from 120,000 feet. At that altitude, the balloon will have a volume of 30 million cubic feet. Red Bull, his sponsor, calls it the largest balloon ever used for manned flight. Fitting, because everything about Red Bull Stratos is larger than life.

Baumgartner hopes to break the unofficial record Joe Kittinger, a retired Air Force colonel from Florida, set in 1960 when he jumped from 102,800 feet during Project Excelsior. If he pulls it off, the 43-year-old Austrian adventurer also will claim records for the highest manned balloon flight and the longest free fall by a skydiver. As if all that weren’t cool enough, Baumgartner also wants to become the first person to exceed the speed of sound — about 700 mph at that altitude — in free fall.

The former military parachutist has made two successful test jumps, from 13 miles and 18 miles up. During his test in July, Baumgartner’s descent from 18 miles took 10 minutes and 36 seconds, and he reached 536 mph during a freefall that lasted 3 minutes and 48 seconds. His capsule took a beating when it landed in the desert outside Roswell, New Mexico, but checked out during testing last week.

The last report from team meteorologist Don Day has a cold front moving east and southeast through the area. Cold temperatures aren’t the problem — it’ll hit 70 below zero where Baumgartner’s headed. It’s the wind that has people worried. It must be blowing less than 2 mph at take-off because the balloon is made of whisper-thin plastic just 0.0008 inches thick. That’s 10 times thinner than the baggie holding your sandwich.

The balloon stands 55 stories tall and weighs 3,708 pounds out of the box. It was constructed from strips of polyethelene that would cover 40 acres if laid out over a field. The balloon will measure 334 feet tall and 424 feet in diameter when Baumgartner reaches peak altitude.

Monday’s launch is slated for dawn. About eight hours before, a crew will clear the runway as another crew, wearing gloves and protective suits to avoid tearing the envelope, carefully removes the balloon from its box and begins laying it out on a protective layer of Herculite.

An hour before launch, mission control will give crew chief Ed Coca the all clear to begin inflating the balloon. The job will take 45 minutes to an hour.

Then, as the sun breaks over the horizon, Baumgartner will begin his ascent.